To support a rotatable roll circumferential wall with a vibration as small as possible and to prevent the danger of a roll deformation resulted from resonance vibration.

This roll for guiding at least one yarn comprises one hollow cylindrical roll circumferential wall 1, a support body 4 for rotatably supporting the roll circumferential wall, at least one electromagnetic bearing 10 having two or more bearing magnetic pole windings 11 distributed in the circumferential direction of the roll circumferential wall 1 on the support body 4, and two or more sensors for measuring the actual position of the roll circumferential wall 1, which are connected to the bearing magnetic pole windings 11 through a control unit 21. The sensors are positioned with a space to the roll circumferential wall 1 and also with a space to the support body 4 so that the actual position of the roll circumferential wall 1 to a constant reference position of the roll circumferential position 1 can be measured.